Spooling process films

ABSTRACT

Spooling apparatus. The apparatus includes an interposer film having a spacer surface and a back surface; a first spacer carried by the interposer film on the spacer surface adjacent a first edge of the interposer film; a second spacer carried by the interposer film on the spacer surface adjacent a second edge of the interposer film, the spacers defining a process-film protective space; and a rotatable core oriented to receive an initial end of the interposer film and to roll up the interposer film with a process film in the process-film protective space with a passive surface of the process film adjacent a surface of the interposer film.

BACKGROUND

Process films (including substrates) find many applications in high-technology device manufacture. A process film typically has an active surface and a passive surface. The passive surface can be handled and manipulated with ease, but functional devices, layered coatings, and components may be formed or placed on the active surface, and as a result the active surface may easily be contaminated or damaged by any physical contact during processing. For this reason, various kinds of cassettes and track systems have been developed tier handling process films in ways that do not risk contaminating their active surfaces. In the semiconductor industry, the front-opening unified pod (FOUP) style of standardized wafer cassette handing is widely used to hold silicon wafers; a wafer can be removed from such a pod for processing or measurement as needed by special tools. Similar processes are used for handling thin-film transistor (TFT) glass substrates. In the plastic patterning industry disposable interleaves are sometimes used for handling such process films as touch-screen and membrane switch constituents.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures are not drawn to scale. They illustrate the disclosure by examples.

FIG. 1A is a perspective view of an example of spooling apparatus.

FIG. 1B is a perspective view of another example of spooling apparatus.

FIG. 1C is a perspective view of another example of spooling apparatus.

FIG. 2A is a sectional view of an interposer film and a process film rolled up around a core with the process film adjacent a back surface of the interposer film according to an example.

FIG. 2B is a sectional view of an interposer film and a process film rolled up around a core with the process film adjacent a spacer surface of the interposer film according to an example.

FIG. 3 is a sectional view of an interposer film and a process film rolled up around a core according to another example.

FIG. 4 is a perspective view of an example of an interposer film with spacers formed as parallelepipeds.

FIG. 5 is a perspective view of an example of an interposer film with frusto-conical spacers.

FIG. 6 is a perspective view of an example of a gas-permeable interposer film with gas-permeable spacers formed as continuous strips.

FIG. 7 is a perspective view of an example of an interposer film formed as a mesh.

FIG. 8 is a perspective view of an example of an interposer film having a textured surface.

FIG. 9 is a perspective, partially cut away, of layers of process film separated by layers of interposer film.

FIG. 10 is a perspective of two strips of process film side-by-side between each layer of interposer film according to an example.

FIG. 11A is a perspective view of an example of an interposer film carrying a plurality of supports on a spacer surface.

FIG. 11B is similar to FIG. 11A and with a process film on the supports.

FIG. 12A is a perspective view of an example of an interposer film carrying a plurality of supports on a back surface.

FIG. 12B is similar to FIG. 12A and with a process film on the supports.

FIG. 13A is a front-side schematic of an example of passive-surface process film spooling apparatus showing process film beginning to move from a full spool toward an empty spool.

FIG. 13B is a back-side schematic of the spooling apparatus shown in FIG. 13A.

FIG. 14 is a flowchart illustrating a method of processing process films according to an example.

FIG. 15 is a flowchart illustrating a method of processing process films according to another example.

FIG. 16 is a flowchart illustrating a method of processing process films according to another example.

DETAILED DESCRIPTION

Illustrative examples and details are used in the drawings and in this description, but other configurations may exist and may suggest themselves. Parameters such as voltages, temperatures, dimensions, and component values are approximate. Terms of orientation such as up, down, top, and bottom are used only for convenience to indicate spatial relationships of components with respect to each other, and except as otherwise indicated, orientation with respect to external axes is not critical. For clarity, some known methods and structures have not been described in detail. Methods defined by the claims may comprise steps in addition to those listed, and except as indicated in the claims themselves the steps may be performed in another order than that given. Accordingly, the only limitations are imposed by the claims, not by the drawings or this description.

Roll-to-roll fabrication of active surfaces on process films has been difficult. In complex processes there often are only limited stages in which a film can be rolled up. This is because rolling up the film results in the active side in one wrap of the roll contacting the passive side in a succeeding wrap. In a process involving coating the active surface with a sensitive or adhesive material such as photoresist or barrier coating, the process must continue in-line through cure and bake steps before the film can be rolled up. In addition, even in fabrication stages where rolling up is possible, contamination and mechanical damage introduced by rolling and re-roiling can damage the active surface or components on it. Even in processes where interleaves are used there is a risk of contamination. Moreover, interleaves can introduce static electric charges that not only can damage components on the active surface but also can attract dust and other forms of small particulate contamination. There has been a need for a way to roll up a process film at various fabrication stages without inflicting damage.

As shown in FIG. 1A, an example of spooling apparatus includes an interposer film generally 100 having a spacer surface 102 and a back surface 104. A first spacer 106 is carried by the interposer film 100 on its spacer surface 102 adjacent first edge 108 of the interposer film. A second spacer 110 is carried by the interposer film 100 on the spacer surface 102 adjacent a second edge 112 of the interposer film 100. A process-film protective space 114 is defined between the first and second spacers. A rotatable core 116 is oriented to roll up the interposer film as indicated by an arrow 118 together with a process film (not shown) in the process-film protective space 114 with a passive surface of the process film adjacent a surface of the interposer film. In this example the interposer film 100 wraps around the core 116 with the spacer surface 102 facing the core, as indicated by an arrow 120 showing the core rotating about its axis 122 in an anticlockwise direction when viewed from a near end 124 of the core 116. The protective space 114, defined between the spacers 106 and 110, extends from the spacer surface 102 to a back surface of an adjacent layer (or wrap) of the interposer film when the film is rolled up.

As shown in FIG. 1B, in some examples the interposer film 100 wraps around the core 116 with the back surface 104 facing the core as indicated by an arrow 126.

In the example of FIG. 1A the core is shown in the form of a solid shaft, but the core may take other forms. FIG. 1C gives an example of spooling apparatus that is similar to that shown in FIG. 1A except that a first flanged wheel 128 adjacent the first edge 108 of the interposer film 100 and a second flanged wheel 130 adjacent the second edge 112 of the interposer film 100 are used as a core rather than a solid shaft.

Referring now to FIG. 2A, a length of interposer film 200 with spacers on either edge is shown rolled up around a core 202. A first portion 204 of the interposer film 200 is closest to the core 202 and carries a first portion 206 of a spacer along one edge and a first portion 208 of a spacer along an opposite edge. The term “portion” refers to one layer (or wrap) of film or spacer extending all the way around the core. A first portion (layer or wrap) is adjacent the core and successive layers or wraps are wound one on top of the previous one as the film and spacers are wound up. The first portions 206 and 208 of the spacers are adjacent to, and in some examples rest on, the core 202.

A second portion 212 of the interposer film 200 carries second portions 214 and 216 of spacers that rest on the first portion 204 of the interposer film. A third portion 218 of the interposer film 200 carries third portions 220 and 222 of spacers that rest on the second portion 212 of the interposer film.

A length of process film 224 is also rolled up around the core. A first portion 226 of the process film 224 is located in a portion 228 of protective space formed between the spacers. As with the interposer film, the first portion 226 of the process film may be considered as a first layer (first wrap) around the core. A first portion 230 of an active surface of the process film 224 carries various items such as features, coatings, functionalisations, patterns, or components 232A, 232B, 232C, and 232D. These items are installed on, formed in, or otherwise placed on the active surface of the process film. A first portion 234 of a passive surface of the process film 224 is adjacent a first portion 236 of a back surface of the interposer film 200. The first portion 234 of the passive surface of the process film 224 is supported by the first portion 236 of the back surface of the interposer film 200. As will be discussed in more detail presently, the process film is tensioned sufficiently to maintain contact between it and the back surface of the interposer film.

The first portion 228 of the protective space extends between the first portion 236 of the back surface of the interposer film and a second portion 238 of the spacer surface of the interposer film. The spacers are sized such that the protective space fully contains the process film without any contact between the spacer surface of the interposer film and the active surface of the process film.

A second portion 240 of the process film 224 is located in a second portion 242 of the protective space between the spacers. A second portion 24.4 of the passive surface of the process film is adjacent a second portion 246 of the back surface of the interposer film.

A spool thus formed may comprise fewer or more, in some examples many more, wraps than the three wraps of interposer film and two wraps of process film shown in FIG. 2A.

FIG. 2B is generally similar to FIG. 2A except that a process film is shown interleaved with an interposer film around a core with a passive surface of the process film adjacent a spacer surface of the interposer film. More particularly, a length of interposer film 248 with spacers on either edge is shown rolled up around a core 250. A first portion 252 of the interposer film is closest to the core and carries a first portion 254 of a spacer along one edge and a first portion 256 of a spacer along an opposite edge. A second portion 258 of the interposer film carries second portions 260 and 262 of spacers that rest on the first portion 252 of the interposer film. A third portion 264 of the interposer film carries third portions 266 and 268 of spacers that rest on the second portion 258 of the interposer film.

A length of process film 270 is also rolled up around the core. A first portion 272 of the process film 270 is located in a portion 274 of protective space formed between the spacers. A first portion 276 of an active surface of the process film carries various items such as features, coatings, functionalisations, patterns, or components 278A, 278B, 278C, and 278D. These items are installed on, formed in, or otherwise placed on the active surface of the process film. A first portion 280 of a passive surface of the process film lies adjacent a first portion 282 of a spacer surface of the interposer film. The first portion 280 of the passive surface of the process film is supported by the first portion 282 of the back surface of the interposer film.

A second portion 284 of the process film is located in a second portion 286 of the protective space between the spacers. A second portion 288 of the passive surface of the process film is adjacent a second portion 290 of the spacer surface of the interposer film. Similarly, a third portion 292 of the process film is located in a third portion 294 of the protective space between the spacers with a third portion 296 of the passive surface of the process film adjacent a third portion 298 of the spacer surface of the interposer film.

FIG. 3 is generally similar to FIG. 2A except that in this example an interposer film 300 is wound up around a core 302 with a first portion 304 of a back surface of the interposer film adjacent to, and in some examples supported by, the core 302. A first portion (or wrap, or layer) 306 of the interposer film 300 carries a first portion 308 of a first spacer and a first portion 310 of a second spacer. A second portion 312 of the interposer film lies on the first portions 308 and 310 of the spacers and in turn carries second portions 314 and 316 of the spacers. A third portion 318 of the interposer film lies on the second portions 314 and 316 of the spacers and in turn carries third portions 320 and 322 of the spacers.

A length of process film 324 is also rolled up around the core 302. A first portion 326 of the process film 324 is located in a first portion 328 of a protective space formed between the spacers. Various features, coatings, functionatisations, patterns or components 330A, 330B, 330C, and 330D are installed or formed on a first portion 332 of an active surface of the process film. A first portion 334 of a passive surface of the process film is adjacent a first portion 336 of a spacer surface of the interposer film. The first portion 328 of the protective space is bounded by the first portion 336 of the spacer surface and a second portion 338 of the back surface of the interposer film. The process film is tensioned sufficiently to hold its passive surface against the spacer surface of the interposer film such that the active surface of the process film does not contact the back surface of the interposer film.

A second portion 340 of the process film 324 is located in a portion 342 of the protective space between the spacers. A second portion 344 of the passive surface of the process film lies on a second portion 346 of the spacer surface of the interposer film. Similarly, a third portion 348 of the process film 324 is located in a third portion 350 of the protective space. A third portion 352 of the passive surface of the process film lies on a third portion 354 of the spacer surface of the interposer film. As with the other portions of the protective space, the third portion 350 of the protective space lies between the back and spacer surfaces of the interposer film; in this instance, the third portion 350 of the protective space lies between the third portion 354 of the spacer surface of the interposer film and a portion of the back surface of a fourth portion (not shown) of the interposer film.

Returning to the example of FIG. 1A, the first spacer 106 is shown as a segmented strip. The second spacer 110 is also shown as a segmented strip. The interposer film and the spacers are made of materials that are sufficiently compliant to roll up around the core 116. In this example the spacers 106 and 110 are adjacent to, and in some examples are in contact with, the core as the rolling up begins. The elements in this and the other figures are not drawn to scale, and the core may actually be larger or smaller relative to the spacers than as depicted in the drawings.

FIG. 4 shows an example of an interposer film 400, a plurality of individual spacer elements 402 located at intervals along a first edge 404 of the interposer, and a plurality of individual spacer elements 406 located at intervals along a second edge 408 of the interposer. in this example the spacer elements are shaped as parallelepipeds, but the shape is not critical and spacer elements having other shapes may be used. For example, FIG. 5 shows an interposer 500 with frusto-conical spacers 502.

The example of FIG. 4 also includes a transverse stiffener 410 embedded in the interposer 400. This stiffener extends from the first edge 404 to the second edge 408, but in other examples the stiffener may not extend this far. A plurality of similar stiffeners may be disposed at intervals along the interposer. The stiffener 410 is shown at right angles to the edges, and therefore it does not interfere with rolling on the interposer onto a core. In other examples the stiffeners may be disposed across the interposer at other angles so long as the stiffeners do not interfere with rolling up the interposer. The interposer may also be formed of a material with anisotropic compliance, retaining transverse stiffness whilst capable of forming a longitudinal roll.

FIG. 6 is an example of an interposer film 600 with first and second spacers 602 and 604 each formed as a continuous strip of material. The spacer material must be sufficiently compliant as to permit rolling up onto a core. In this example the interposer film and the spacers have been made gas-permeable by a plurality of openings such as openings 606 in the interposer film, openings 608 in the first spacer, and openings 610 in the second spacer. Making one or more of the interposer film and the spacers gas-permeable facilitates escape of gases that may be emitted by a process film adjacent the interposer film 600 and ingress and flow of reactive gaseous materials to allow in-spool process changes to the process film. The openings may be formed by any convenient method. In other examples the interposer film and spacer materials may lack special openings but may be sufficiently porous as to be gas permeable.

FIG. 7 gives an example of an interposer film 700 formed of mesh material. As with the example of FIG. 6, the mesh facilitates movement of gases. In this example the interposer 700 carries first and second spacers 702 and 704 formed as segmented strips, and in other examples a mesh interposer film may carry any other suitable spacers.

FIG. 8 is an example of an interposer film 800 having a textured spacer surface 802. The texturing may be in any suitable pattern to avoid or mitigate stiction between the textured surface and a process film that may contact the surface, or to facilitate access of gases or reactive gaseous materials to the process film. In other examples aback surface 804 of the interposer film 800 may be textured. In this example the interposer film 800 carries first and second spacers 806 and 808 formed as segmented strips, but the spacers may take other forms, for example as described above.

FIG. 9 shows wraps of process film separated from each other by wraps of interposer film. A first portion (layer or wrap) 900 of an interposer film carries first spacers 902 and second spacers 904. A second portion 906 of the interposer film carries first spacers 908 and second spacers 910 defining therebetween a protective space 912. A third portion 914 of the interposer film carries first spacers 916 and second spacers 918 defining therebetween a protective space 920. A passive surface 922 of a first portion 924 of a process film is disposed adjacent a back surface 926 of the first portion 900 of the interposer film. An active surface 928 of the first portion 924 of the process film carries components, layers or features 930A and 930B. The active surface 928 resides in the protective space 912 and makes no contact with any other portion of the process film or any portion of the interposer film. A passive surface 932 of a second portion 934 of the process film is disposed adjacent a back surface 936 of the second portion 906 of the interposer film. An active surface 938 of the second portion 934 of the process film resides in the protective space 920 and makes no contact with any other portion of the process film or any portion of the interposer. The active surface 938 may carry components, layers or features (not shown). A passive surface 940 of a third portion 942 of the process film is disposed adjacent a back surface 944 of the third portion 914 of the interposer film.

More than one process film strip may be disposed adjacent a single interposer film. As shown in FIG. 10, a first portion 1000 of an interposer film carries a spacer 1002 adjacent a first edge of its spacer surface 1004, a spacer 1006 adjacent a second edge, and a spacer 1008 in the middle. A second portion 1010 of the interposer film, disposed beneath a back surface 1012 of the first portion 1000 of the interposer film, carries a spacer 1014 adjacent a first edge of its spacer surface 1016, a spacer 1018 adjacent a second edge, and a spacer 1020 in the middle.

A first portion 1022 of a first process film 102.4 is disposed in a protective space between the spacers 1014 and 1020. A second portion 1026 of the first process film 1024 is disposed in a protective space between spacers (not shown) carried by a third portion (not shown) of the interposer film. A passive surface 1028 of the first portion 1022 of the first process film 1024 is adjacent the back surface 1012 of the first portion 1000 of the interposer film. A passive surface 1030 of the second portion 1026 of the first process film 1024 is adjacent a back surface 1032 of the second portion 1010 of the interposer film.

A first portion 1034 of a second process film 1036 is disposed in a protective space between the spacers 1018 and 1020. A second portion 1038 of the second process film 1036 is disposed in a protective space between spacers (not shown) carried by the third portion (not shown) of the interposer film. A passive surface 1040 of the first portion 1034 of the second process film 1036 is adjacent the back surface 1012 of the first portion 1000 of the interposer film. A passive surface 1042 of the second portion 1038 of the second process film 1036 is adjacent the back surface 1032 of the second portion 1010 of the interposer film.

An active surface 1044 of the first portion 1022 of the first process film 1024 may carry components, layers or features (not shown) and is not touched by the interposer film or by any other portions of process film. Similarly, an active surface 1046 of the second portion 1026 of the first process film 1024, an active surface 1048 of the first portion 1034 of the second process film 1036, and an active surface 1050 of the second portion 1038 of the second process film 1036, are untouched by the interposer film or any other portions of process film. For example a component 1052 is disposed on the active surface 1046, a component 1054 is disposed on the active surface 1048, and a component 1056 is disposed on the active surface 1050.

As shown in FIG. 11A, a plurality of supports 1100, 1102, 1104, and 1106 may be carried by an interposer film 1108. The supports are carried on a spacer surface 1110 of the interposer film 1108, as are spacers 1112 along one edge of the interposer 1108 and spacers 1114 along another edge of the interposer 1108. FIG. 11B is similar to FIG. 11A except that a process film 1116 is shown in a protective space between the spacers 1112 and 1114. An active surface 1118 of the process film 1116 is in contact with the supports and has a component 1120. The support 1100 contacts the active surface 1118 of the process film 1116 only along a first edge 1122 where it will not do any damage to components or other active elements in any active region of the process film. Similarly the support 1102 contacts the active surface 1118 only along a second edge 1124, remote from any active region of the process film.

In FIGS. 11A and 11B, the supports are carried on the spacer surface of the interposer. As shown in FIGS. 12A and 12B, supports 1200 and 1202 may be carried on a back surface 1204 of an interposer film 1206. Spacers 1208 are carried along one edge of a spacer surface 1210 of the interposer 1206 and spacers 1212 along another edge of the interposer 1206. A portion 1214 of a process film 1216 is supported by the supports 1200 and 1202 in a protective space between spacers (not shown) of another portion (not shown) of the interposer film. As in the example of FIGS. 11A and 11B, an active surface 1218 of the process film 1216 is supported by the supports 1200 and 1202 along edges that are remote from any components such as a component 1220 or any active region of the active surface 1218 of the process film 1216.

In the foregoing two examples, the supports comprise spaced-apart parallelepipeds, but in other examples the supports may take the for of segmented strips, continuous strips, or other suitable shapes as desired.

An example of passive-surface process film spooling apparatus generally 1300 is shown in FIGS. 13A and 13B. A first cassette 1302 contains a spool 1304 of a process film 1306 wound up in layers on a core 1308. On the spool 1304, each layer of the process film 1306 occupies a protected space formed by one or more layers of a first interposer film 1310 in a manner as described above. The process film 1306 unwinds from the spool 1304, exits the first cassette 1302 through an opening 1312, and passes through a process station 1314. Any suitable process may be carried out on the process film 1306 in the process station 1314. From the process station 1314, the process film 1306 enters a second cassette 1316 through an opening 1318. The process film 1306 is interleaved with a second interposer film 1320 and both films are wound up on a core 1322 to forma spool 1324 with the process film 1306 occupying protective spaces formed by layers of the second interposer film 1320 in a manner as described above. Eventually all of the process film 1306 has been transferred from the first cassette 1302 to the second cassette 1316. Then the second cassette 1316 can be removed from the apparatus 1300 and used to safely store or transport the process film 1306.

The process film 1306 may be guided from the first cassette 1302 through the process station 1314 to the second cassette 1316, for example by a first tension roller 1326 between the first cassette 1302 and the process station 1314 and a second tension roller 1328 between the process station 1314 and the second cassette 1316. The first and second tension rollers contact the process film 1306 only on a passive side 1330. Other guides may also be used, such as a draw roller 1332 and a nip wheel 1334 between the tension roller 1326 and the process station 1314, and a draw roller 1336 and a nip wheel 1338 between the process station 1314 and the tension roller 1328.

As the process film unwinds from the spool 1304, the first interposer film 1310 also unwinds and exits the first cassette through the opening 1312. The first interposer film may be wound up to form a spool 1340 on a core 1342. The first interposer film may pass over one or more guides such as a tension roller 1344 as it is unwound from the spool 1304 in the first cassette 1302 and is wound onto the spool 1340. When the process film 1306 and the first interposer film 1310 have been unwound from the spool 1304 and the first interposer film 1310 has been wound onto the spool 1340, the spool 1340 of interposer film may be removed from the apparatus 1300 and reused later, left in situ, or wound back into the cassette without process film for storage.

The second interposer film 1320 may be obtained by unwinding from a spool 1346 on a core 1348. The second interposer film 1320 may pass over one or more guides such as a tension roller 1350 and enters the second cassette 1316 through the opening 1318.

In some examples the opening 1312 may be sealed with a cover 1352 except when the films are being unwound from the spool 1304. Similarly, the opening 1318 may be sealed with a cover 1354 except when the films are being wound up on the spool 1324.

As the process film is wound onto the spool 1324, it may be tensioned by a servo motor 1356 that drives the core 1322. In some examples the process film is also tensioned by one or more of the tension roller 1328, the tension roller 1326, or any other components. In some examples a servo motor (not shown) may be mechanically coupled to the core 1308 and may be used to tension the process film as it is unwound. In some examples a friction brake 1358 applied to a drum 1360 coupled to the core 1308 may be used to tension the process film as it is unwound. Instead of the servo motor 1356, some other kind of motor or a hand crank may be used to provide torque to wind the process and interposer films onto the core 1322.

A servo motor 1362 or other suitable motive device may be used to wind the first interposer film 1310 onto the core 1342 as the process film 1306 and the first interposer film 1310 unwind from the spool 1304. Another servo motor (not shown) or a friction brake 1364 applied to a drum 1366 carried by or coupled to the core 1348 may be used to tension the second interposer film 1320 as it unwinds from the spool 1346.

FIG. 14 gives an example of a method of processing process films. The method. includes providing an interposer film having a spacer surface and a back surface, the spacer surface having a first spacer adjacent a first edge of the interposer film and a second spacer adjacent a second edge of the interposer film, and at least one protective space defined between the first and second spacers (1400); and winding a process film and the interposer film onto a core with the process film disposed in the protective space between the first and second spacers and a passive surface of the process film adjacent a surface of the interposer film (1402).

FIG. 15 gives another example of a method of processing process films. As in the previous example, a first interposer film having a spacer surface and a back surface is provided, the spacer surface having a first spacer adjacent a first edge of the interposer film and a second spacer adjacent a second edge of the interposer film with least one protective space defined between the first and second spacers (1500). The first interposer film is tensioned (1502). In some examples a process film is tensioned at less tension than the first interposer film (1504). The films are wound onto a core with the process film disposed in the protective space between the first and second spacers and with a passive surface of the process film adjacent a surface of the interposer film (1506). Tension in the interposer film, not tension in the process film, forms the spool.

In some examples a process is carried out on the process film as the film is being wound up (1508). This procedure has been discussed previously in connection with FIGS. 13A and 13B, where the process film is fed through a process station and then wound up.

In other examples the process is carried out after the films have been wound up (1510). As one example, the spooled-up film may be placed into a process station and the process performed on the entire spool at once. An interposer film that is porous or perforated as described previously may be used in this instance.

FIG. 16 gives another example of a method of processing process films. An unprocessed process film spooled with a first interposer film is provided with a passive surface of the process film adjacent a surface of the interposer film (1600). The films are unwound (1602). The process film is fed through a process station (1604) and the first interposer film is spooled up (1606).

In some examples the method continues with providing a second interposer film (1608). The process film is spooled with the second interposer film, a passive surface of the process film adjacent a surface of the second interposer film (1610). The process film may be tensioned at a lesser tension than at least one of the first and second interposer films (1612).

In other examples, instead of spooling up the first interposer film, the process film is fed back to the first interposer film and is again spooled up with the first interposer film (1614), and no second interposer film is needed.

A spool of process film disposed in the protective spaces provided by the interposer film and its spacers, and with an active surface of the process film thereby protected from any contact with either the interposer film or other layers of the process film, may be enclosed in a cassette. A cassette containing such a spool can easily be transported without damaging the process film.

The interposer film may be fabricated of any thin compliant material, such as plastic, paper, metal, glass, composite, or the like.

During spooling, the interposer film can be tensioned to form the spool, and very little tension need be applied to the process film, further protecting it. The core may be rotated by a servo motor (for example, as shown in FIG. 13B) for precise control of speed and torque, by a hand crank (not shown) which also may offer good control of speed and torque, or some other suitable device.

Apparatus and methods as described make it possible to handle process films in such a way that active surfaces of the films are not touched during unwinding or winding up or white spooled. Wound-up spools of process film can easily be protected from contamination by dust and other damaging debris during transport or any time the process film is not being processed. This flexibility allows different processes to be run at different rates. Some processing, for example long-term low-temperature baking, may be done while the film is spooled up. If the spool of film is enclosed in a cassette, the cassette can readily be transported between facilities and processes outside of a clean environment. Fabrication processes can be broken down into a smaller granularity, allowing for optimization and easy process development at pilot scale or customization at volume scale. The same system can handle films of various widths, thicknesses, and moduli. Films can be spooled with independent tension between the spool formation and tension of the film, and films can be stored with low tension applied, leading to a reduction in mechanical deformation during storage. Cassettes can carry tracking, content, and process data any of which can be read without reference to the actual film, facilitating efficient process management and quality control. 

We claim:
 1. Spooling apparatus comprising: an interposer film having a spacer surface and a back surface; a first spacer carried by the interposer film on the spacer surface adjacent a first edge of the interposer film; a second spacer carried by the interposer film on the spacer surface adjacent a second edge of the interposer film, the spacers defining a process-film protective space; and a rotatable core oriented to receive an initial end of the interposer film and to roll up the interposer film with a process film in the process-film protective space with a passive surface of the process film adjacent a surface of the interposer film.
 2. The apparatus of claim 1 wherein the spacers are selected from among a segmented strip, a compliant strip, and a plurality of spacer elements.
 3. The apparatus of claim 1 wherein the interposer film comprises at least one of a surface-textured material, a mesh, an anisotropically-compliant material, and one or more transverse stiffening elements.
 4. The apparatus of claim 1 Wherein one or more of the interposer film, the first spacer, and the second spacer comprise gas-permeable material.
 5. The apparatus of claim 1 and further comprising a plurality of supports carried by the interposer film and disposed to support an active surface of the process film at points remote from any active portions of the active surface of the process film.
 6. The apparatus of claim 1 and further comprising one or more additional spacers carried by the interposer film between the first and second spacers, the additional spacers dividing the protective space into protective regions each sized to accommodate a process film.
 7. The apparatus of claim 1 and further comprising: an interposer film core on which the interposer film is rolled up and from which the interposer film may be unrolled; and a tensioner coupled to the interposer film core.
 8. The apparatus of claim 1 and further comprising an interposer film tension roller disposed to feed the interposer film to the rotatable core.
 9. The apparatus of claim 1 and further comprising a motor coupled to the rotatable core.
 10. The apparatus of claim 1 and further comprising: a cassette enclosing the rotatable core, the cassette sized to accommodate a spool of interposer film and process film rolled up on the rotatable core, a wall of the cassette defining an opening sized to accommodate the interposer and process films; and a removable cover on the opening.
 11. A method of processing process films, the method comprising: providing an interposer film having a spacer surface and a back surface, the spacer surface having a first spacer adjacent a first edge of the interposer film and a second spacer adjacent a second edge of the interposer film, and at least one protective space defined between the first and second spacers; and winding a process film and the interposer film onto a core with the process film disposed in the protective space between the first and second spacers and a passive surface of the process film adjacent a surface of the interposer film.
 12. The method of claim 11 wherein winding the process and interposer films onto the core comprises: tensioning the interposer film; and tensioning the process film at a lesser tension than the interposer film.
 13. The method of claim 11 and further comprising carrying out a process on the process film after the film has been wound onto the core.
 14. A method of processing process films, the method comprising: providing unprocessed process film spooled with a first interposer film, a passive surface of the process film adjacent a surface of the first interposer film; unwinding the films; feeding the process film through a process station; and spooling the interposer film.
 15. The method of claim 14 and further comprising: providing a second interposer film; and spooling the process film with the second interposer film, a passive surface of the process film adjacent a surface of the second interposer film.
 16. The method of claim 15 and further comprising tensioning the process film at a lesser tension than at least one of the first and second interposer films. 